Image forming equipment typically uses supplies such as toner, ink, paper and others. They are often called consumables in the trade, as they are expended and need to be replenished from time to time in regular use of the equipment. Copiers, printers, and fax machines are some examples of such image forming equipment. One type uses toner cartridges, each including a photoconductive drum, a developing device to form a toner image, a cleaning device to remove residual toner from the drum, and other components, and typically print on cut sheets of paper. Other types use toner bottles or other printing methods, such as line printing and ink-jet printing.
A user who needs to replace or add supplies may purchase them as needed or may take them from an inventory the user maintains, for which purchases from suppliers are made less frequently. For greater convenience, remote diagnostic systems are offered to connect equipment such as copiers to a service center via the public switched telephone network in order to automatically transmit status information regarding the image forming devices to the service center. Japanese Laid-Open Publications 8-152816 and 8-152817 discuss such systems. According to the publications, usage information regarding toner and paper for copiers is transmitted to the service center, and the service center manages an inventory of supplies at the user side based on the transmitted information. When the inventory becomes depleted, the service center plans replenishment. In the publications, as understood, the entity that would send supplies to the user side is predetermined, and the system does not provide the user with information regarding other possible sources of relevant supplies.